A roadarm for a tracked vehicle failed during preproduction vehicle testing. The arm was a weldment of two cored low-alloy steel sand castings specified to ASTM A 148, grade 120–95. A maximum carbon content of 0.32% was specified. The welding procedure called for degreasing and gas metal arc welding; neither preheating nor postheating was specified. The filler metal was E70S-6 continuous consumable wire with a copper coating to protect it from atmospheric oxidation while on the reel. Analysis of the two castings revealed that the carbon content was higher than specified, ranging from 0.40 to 0.44%. The fracture occurred...